Hole cutter with multiple fulcrums

ABSTRACT

A hole cutter has a cylindrical blade body including a cutting edge and one or more axially-elongated apertures formed within a side wall of the blade body. The axially-elongated aperture is configured to receive a lever, such as a screwdriver, therethrough. Each axially-elongated aperture includes a first fulcrum axially spaced adjacent to the cutting edge, a second fulcrum axially spaced further away from the cutting edge than the first fulcrum, and optionally a third fulcrum axially spaced between the first and second fulcrums. A lever, such as a screwdriver, can be inserted into the aperture and placed against each of the fulcrums to lever slugs out of the interior of the blade body.

This application is a continuation of co-pending U.S. Patent ApplicationNo. 29/496,442, filed Jul. 14, 2014, which is a divisional of U.S.Patent Application No. 29/465,441, filed Aug. 28, 2013, now U.S. Pat.No. D711,441, issued Aug. 19, 2014, which is a divisional of U.S. PatentApplication No. 29/417,810, filed Apr. 9, 2012, now U.S. Pat. No.D692,470, issued Oct. 29, 2013, titled “HOLE SAW”, which is acontinuation of the following applications: U.S. Patent Application No.29/353,762, filed Jan. 13, 2010, now U.S. Pat. No. D690,334, issued Sep.24, 2013, titled “HOLE SAW”; U.S. Patent Application No. 29/353,759,filed Jan. 13, 2010, now U.S. Pat. No. D659,176, issued May 8, 2012,titled “HOLE SAW”; U.S. patent application Ser. No. 13/006,117, filedJan. 13, 2011, titled “HOLE CUTTER WITH CHIP EGRESS APERTURE,” which isa continuation-in-part of U.S. patent application Ser. No. 12/687,078,filed Jan. 13, 2010; and U.S. patent application Ser. No. 13/006,080,filed Jan. 13, 2011, now U.S. Pat. No. 8,579,555, issued Nov. 12, 2013,titled “HOLE CUTTER WITH AXIALLY-ELONGATED APERTURE DEFINING MULTIPLEFULCRUMS,” which is a continuation-in-part of U.S. patent applicationSer. No. 12/687,065 filed Jan. 13, 2010, now U.S. Pat. No. 8,579,554,issued Nov. 12, 2013, all of which are hereby expressly incorporated byreference as part of the present disclosure.

FIELD OF THE INVENTION

The present invention relates to hole cutters, and more particularly, tohole cutters with apertures in their side walls that define fulcrums forinserting and levering a tool, such as a screwdriver, to remove workpiece slugs from the interiors of the hole cutters.

BACKGROUND

A hole cutter, or hole saw, is a type of cutter used in drillingcircular holes in various materials, such as wood, metal, drywall, etc.A hole cutter typically has a substantially cylindrical body thatdefines a side wall, a circular cutting edge with teeth located at oneend of the body and designed to cut a work piece during rotation of thecutter, and a cap located at the end of the body opposite the cuttingedge. The cap typically includes threads, holes or other structureadapted to allow the hole cutter to be drivingly connected to a drill,such as through an arbor. In use, the circular cutting edge creates acircular hole in a work piece and, in turn, removes a circular workpiece slug therefrom. Typically, after the hole is cut in the workpiece, the work piece slug is retained within the hollow interior of thehole cutter and must be removed therefrom prior to cutting another hole.

Prior art hole cutters include apertures or slots formed in the sidewalls of the hole cutters that allow users to insert a lever, such as ascrewdriver, through the side wall and into the interior of the holecutter to, in turn, lever or otherwise urge the slug out of the holecutter. This manual slug removal task can be time-consuming and takesubstantial effort on the part of the user. A slug may be difficult toextract from within the body of a cutter, even with a hole cutter thatincludes slug removal apertures or slots, because the slug can becometightly wedged in the cutter or because the slug removal apertures orslots are not aligned with the slug. For example, a slug may becomewarped or cracked and thus firmly lodged within the hole cutter. Asanother example, some work pieces, such as woods, contain sticky orglue-like residue that inhibits slug removal. As yet another example,thicker and thinner work pieces will create slugs of differingthicknesses and slugs positioned at different locations within the holecutter. A thick work piece can create a thick slug that is pushed deepinto the body of the hole cutter, whereas a thin work piece can create athin slug located near the cutting edge. Accordingly, slugs often do notsimply “pop” out of the cutter when worked by a tool. Slugs often slideshort distances, twist, tilt or otherwise gradually or incrementallymove along the inside of the cutter. The apertures in the side walls ofprior art hole cutters can be relatively short, and therefore may beused only to remove either relatively thin or relatively thick workpiece slugs, but not both types of slugs, and possibly not slugs ofmedium thicknesses. Other prior art hole cutters have plural aperturesthat are axially and angularly spaced relative to each other, whereineach aperture is relatively short in length. These types of aperturesmay require moving the screwdriver or other lever from one aperture toanother in order to lever a slug out of the hole cutter. Further, no oneaperture may be properly positioned for a particular slug thickness, ora particular slug positioning within the interior of the hole cutter,further contributing to the difficult and time consuming nature of theslug removal process.

Accordingly, it is an object of the present invention to overcome one ormore of the above-described drawbacks and/or disadvantages of the priorart.

SUMMARY OF THE INVENTION

In accordance with a first aspect, the present invention is directed toa hole cutter comprising a substantially cylindrical blade body defininga cutting edge and at least one axially-elongated aperture formedthrough the blade body. The axially-elongated aperture is configured toreceive therethrough a lever, such as a screwdriver, for removing a workpiece slug from the interior of the blade body. The blade body defineswithin the axially-elongated aperture a plurality of fulcrums forengaging the lever and levering slugs out of the interior of the bladebody. The fulcrums include a first fulcrum axially spaced adjacent tothe cutting edge and a second fulcrum axially spaced further away fromthe cutting edge than the first fulcrum. Some embodiments of the presentinvention further include a third fulcrum axially spaced between thefirst and second fulcrums.

In some embodiments of the present invention, such as for relativelylarge diameter hole cutters, the hole cutter comprises a plurality ofthe axially-elongated apertures angularly spaced relative to each other.In other embodiments of the present invention, such as for relativelysmall diameter hole cutters, the hole cutter comprises only oneaxially-elongated aperture. In some such embodiments, the relativelysmall diameter hole cutters have diameters of about 1 7/16 inch or less,and the relatively large diameter hole cutters have diameters of about1½ inch or greater. In some such embodiments, the axially-elongatedaperture(s) is (are) oriented substantially parallel to the axis of thehole cutter for hole cutters having diameters of about 1 7/16 inch orless, and the axially-elongated apertures are oriented at an acute anglerelative to the axis of the hole cutter for hole cutters havingdiameters of about 1½ inch or greater.

In some embodiments of the present invention, the first fulcrum islocated at approximately one end of the axially-elongated aperture, andthe second fulcrum is located at approximately an opposite end of theaperture relative to the first fulcrum. In some embodiments, a thirdfulcrum is located approximately midway between the first and secondfulcrums.

In some embodiments of the present invention, the second fulcrum isangularly and axially spaced relative to the first fulcrum, and in someembodiments, a third fulcrum is angularly and axially spaced between thefirst and second fulcrums. The hole cutter defines a direction ofrotation that is the cutting direction of the cutting edge. In some suchembodiments, the axially-elongated aperture defines a first end axiallyspaced adjacent to the cutting edge, and a second end axially spacedfurther away from the cutting edge than the first end and angularlyspaced relative to the first end in a direction opposite to the cuttingdirection. In some such embodiments, the axially-elongated aperturedefines an axially-elongated slot oriented at an acute angle relative tothe axis of the blade body. The acute angle is at least about 30°, andpreferably is within the range of about 35° to about 60°.

In some such embodiments, the first fulcrum is axially spaced from thecutting edge a first distance within the range of about ½ inch to about1 inch, the second fulcrum is angularly spaced relative to the firstfulcrum and is axially spaced from the cutting edge a second distancewithin the range of about 1½ to about 2 inches, and the third fulcrum isangularly and axially spaced between the first and second fulcrums andis axially spaced from the cutting edge a third distance within therange of about 1 inch to about 1½ inches. In some embodiments of thepresent invention, the first distance of the first fulcrum is configuredfor levering slugs having thicknesses of about ½ inch or less, the thirddistance of the third fulcrum is configured for levering slugs havingthicknesses of about 1 inch or less, and the second distance of thesecond fulcrum is configured for levering slugs having thicknesses ofabout 1½ inches or less.

In some embodiments of the present invention, the axially-elongatedaperture defines a first end adjacent to the cutting edge, and the firstend is axially spaced from the cutting edge a first distance within therange of about 15/100 inch to about ⅜ inch. In some such embodiments,the cutting edge is defined by a plurality of saw teeth including tipsand gullets between the tips, and the first distance is measured fromeither (i) a deepest gullet of the cutting edge, or (ii) a planeextending between tips of unset teeth of the cutting edge.

In some embodiments of the present invention, each fulcrum is defined bya fulcrum surface oriented substantially parallel to the cutting edge.In some such embodiments, the fulcrum surface is rectilinear,curvilinear or both. In some such embodiments, the hole cutter includesa non-working end on the opposite end of the blade body relative to thecutting edge, and each fulcrum is formed on the edge of the respectiveaperture adjacent to, or on the side of, the non-working end of the holecutter. In some such embodiments, each of a plurality of fulcrumsdefines a recess in said edge of the respective aperture adjacent to, oron the side of, the non-working end of the hole cutter.

In accordance with another aspect, the present invention is directed toa hole cutter comprising a substantially cylindrical blade body defininga cutting edge and at least one axially-elongated aperture formedthrough the blade body. The axially-elongated aperture is configured toreceive therethrough a lever for removing work piece slugs from theinterior of the blade body. The blade body defines within theaxially-elongated aperture first means axially spaced adjacent to thecutting edge for engaging the lever and levering slugs havingthicknesses within a first range of thicknesses out of the blade bodyand second means axially spaced further away from the cutting edge thanthe first means for engaging the lever and levering slugs out of theblade body having thicknesses within a second range of thicknessesgreater than the first range of thicknesses. Some embodiments of thepresent invention further include third means axially spaced between thefirst and second means for engaging the lever and levering slugs out ofthe blade body having thicknesses within a range of thickness betweenthe first and second range of thicknesses.

In some embodiments of the present invention, each of the first, secondand third means is a respective fulcrum. In some embodiments of thepresent invention, the second means is angularly spaced relative to thefirst means, and the third means is angularly spaced between the firstand second means. In some such embodiments, the third means is axiallyand angularly spaced approximately midway between the first and secondmeans. In some embodiments, the at least one axially-elongated aperturedefines an axially-elongated slot.

In some such embodiments, the hole cutter defines a direction ofrotation that is the cutting direction of the cutting edge, and theaxially-elongated aperture defines a first end axially spaced adjacentto the cutting edge, and a second end axially spaced further away fromthe cutting edge than the first end and angularly spaced relative to thefirst end in a direction opposite the cutting direction. In some suchembodiments, the first means is axially spaced from the cutting edge afirst distance within the range of about ½ inch to about 1 inch, thesecond means is angularly spaced relative to the first means and isaxially spaced from the cutting edge a second distance within the rangeof about 1½ to about 2 inches, and the third means is angularly andaxially spaced between the first and second means and is axially spacedfrom the cutting edge a third distance within the range of about 1 inchto about 1½ inches. In some embodiments, the first means is for leveringslugs having thicknesses of less than about ½ inch, the third means isfor levering slugs having thicknesses of less than about 1 inch, and thesecond means is for levering slugs having thicknesses of less than about2 inches. Preferably, at least a portion of each of the first, secondand third means is substantially parallel to the cutting edge.

One advantage of the hole cutters of the present invention is that theycan provide a relatively quick, easy, and effective means to extractslugs from inside the hole cutters. Another advantage of the holecutters of the present invention is that they provide multiple fulcrumsat different axial locations, and in some embodiments, angularlocations, to facilitate aligning the fulcrums with a variety of workpiece slugs of different thicknesses. Yet another advantage of the holecutters of the present invention is that they provide multiple fulcrumswithin the same axially-elongated aperture and thereby allow a user towork a slug out of the cutter by using multiple fulcrums withoutremoving the lever, such as a screwdriver, from the aperture.

These and other advantages of the present invention, and/or of thecurrently preferred embodiments thereof, will become more readilyapparent in view of the following detailed description of currentlypreferred embodiments and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a hole cutter blade of the presentinvention prior to being formed into a cylindrical blade body shape.

FIG. 2 is a perspective view of another embodiment of a hole cutterembodying the present invention.

FIG. 3 is a side elevational view of the blade of the hole cutter ofFIG. 2 prior to being formed into a cylindrical blade body shape.

FIG. 4 is a side elevational view of another embodiment of a hole cutterblade of the present invention used for smaller diameter hole cuttersand prior to being formed into a cylindrical blade body shape.

FIG. 5 is a side elevational view of another embodiment of a hole cutterblade of the present invention used for smaller diameter hole cuttersand prior to being formed into a cylindrical blade body shape.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

In FIG. 1, a blade body of a hole cutter embodying the present inventionis indicated generally by the reference numeral 10. The term “holecutter” is used here to mean a tool that cuts holes in work pieces, suchas wood or metal work pieces, and includes without limitation hole saws.The blade body 10 is shown in FIG. 1 in its flattened state; however, aswill be recognized by those of ordinary skill in the pertinent art basedon the teachings herein, the blade body 10 is rolled or otherwise formedinto a substantially cylindrical shape to form the hole cutter. Theblade body 10 comprises a side wall 12 that extends around an axis ofrotation “X” of the hole cutter to define a substantially cylindricalblade body. One end of the blade body is provided with a cutting edge 14oriented substantially perpendicular to the axis of rotation X, and theopposing end of the blade body defines a rim 16. A cap (not shown) isfixedly secured to the rim 16 to enclose the respective end of the holecutter. The end of the hole cutter opposite the cutting edge 14 andincluding the rim 16 and a cap (not shown) attached thereto is referredto herein as the “non-working” end of the hole cutter. As recognized bythose of ordinary skill in the pertinent art, the cap (not shown) mayinclude a threaded hub and pin apertures so that the hole cutter can becoupled to, and driven by, an arbor drivingly connected to a power tool,such as an electric drill. As shown in FIG. 1, the cutting edge 14 isdefined by a plurality of teeth with gullets extending between theteeth. However, as may be recognized by those of ordinary skill in thepertinent art based on the teachings herein, the cutting edge may bedefined by any of numerous different tooth forms or other cutting edgeforms that are currently known or that later become known. Similarly,although the blade body 10 is formed from sheet metal that is rolled orotherwise formed into the cylindrical blade body 10 of the hole cutterand is, in turn, welded or otherwise attached to a cap, the hole cuttermay be formed in any of numerous other ways that are currently known, orthat later become known. For example, the end cap and side wall 12 maybe spun, drawn, molded or otherwise formed in one part.

As shown in FIG. 1, the blade body 10 defines two axially-elongatedapertures or slots 18 formed through the side wall 12 thereof. As can beseen, the two slots 18 are angularly spaced relative to each other onthe cylindrical blade body 10. In the illustrated embodiment, the twoslots 18 are approximately equally spaced relative to each other, i.e.,the two slots are spaced about 180° relative to each other. In variousembodiments of the invention, each slot 18 has an axial depth D5 (D4−D2)ranging from about 1⅛ inches to about 1⅘ inches. In the illustratedembodiment, each slot 18 has an axial depth D5 of about 1⅓ inches. Incertain embodiments, each slot 18 has a circumferential length L rangingfrom about ⅖ inch to about 1⅘ inches. In the illustrated embodiment,each slot 18 has a circumferential length L of about 1⅕ inches. Asdescribed in further detail below, each axially-elongated aperture orslot 18 is configured to receive therethrough a lever, such as a screwdriver, for removal of a work piece slug located within the interior ofthe blade body 10.

The number of axially-elongated apertures or slots 18 formed through theside wall 12 of the hole cutter depends on the size of the hole cutter.As a general rule, the larger the diameter of the hole cutter, thegreater is the number of axially-elongated apertures or slots 18 thatcan be formed through the cylindrical blade body 10. In the currentlypreferred embodiments of the present invention, relatively smalldiameter hole cutters (e.g., about 9/16 inch diameter to about 13/16inch diameter) have one slot 18 oriented substantially parallel to theaxis X of the hole cutter, larger diameter hole cutters have two slots18 (e.g., about ⅞ inch diameter to about 1 7/16 inches diameter)oriented substantially parallel to the axis X of the hole cutter, stilllarger diameter hole cutters (e.g., about 1½ inches diameter to about 3⅜inches diameter) have two larger area slots 18 that are oriented atacute angles relative to the axis X of the hole cutter, and still largerdiameter hole cutters (e.g., about 3½ inches diameter to about 6 inchesdiameter) have four larger area slots 18 oriented at acute anglesrelative to the axis X of the hole cutter. In the currently preferredembodiments of the hole cutters having multiple axially-extending slots18, the axially-extending slots 18 are approximately equally spacedrelative to each other about the axis X of the hole cutter, i.e., ifthere are two axially-extending slots 18 they are angularly spaced about180° relative to each other, if there are three axially-extending slots18 they are angularly spaced about 120° relative to each other, if thereare four axially-extending slots 18 they are angularly spaced about 90°relative to each other, etc. However, as may be recognized by those ofordinary skill in the pertinent art based on the teachings herein, theaxially-extending apertures or slots 18 need not be equally spacedrelative to each other, nor do all axially-elongated apertures or slots18 on the same hole cutter need to define the same aperture area or slotconfiguration.

In the illustrated embodiment, as shown in FIG. 1, eachaxially-elongated aperture or slot 18 includes three fulcrums 20A, 20Band 20C axially and angularly spaced relative to each other. However, asmay be recognized by those of ordinary skill in the pertinent art basedon the teachings herein, the slot 18 may include fewer than threefulcrums, or more than three fulcrums. The fulcrums 20A, 20B and 20C arerecessed edge surfaces of the side wall 12 of the blade body 10 that areformed on the edge of a respective axially-extending aperture or slot 18that is adjacent to, or on the side of, the non-working end of the holecutter. In the embodiment of FIG. 1, the fulcrums 20A, 20B and 20Cextend linearly in a direction substantially perpendicular to the axisof rotation X of the hole cutter or substantially parallel to thecutting edge 14. Accordingly, a common tool, such as a screw driver, canbe inserted into the axially-extending aperture or slot 18, slipped intoengagement with a respective fulcrum 20A, 20B or 20C, and manipulated asa lever against the respective fulcrum 20A, 20B or 20C to pry or push aslug out of the interior of the blade body 10. Each fulcrum 20A, 20B and20C defines a width W1 that is sufficient to support a common tool orimplement, such as the elongate shaft of an ordinary screw driver, e.g.,a number 2 screw driver. Preferably, the recess of each fulcrum 20A, 20Band 20C defines a width W1 that is least about ¼ inch to allow insertiontherein of a number 2 screw driver (which requires a width or clearanceof about 0.27 inch), and preferably is within the range of about ¼ inchto about ⅓ inch. As can be seen, the recessed surface of each fulcrum20A, 20B, and 20C is oriented substantially parallel to the cutting edge14, and is located on the side of the axially-extending aperture or slot18 opposite the cutting edge 14. In addition, each fulcrum 20A, 20B and20C is recessed within the respective side edge of the axially-extendingaperture or slot 18 so that a side edge or lip 21 is formed at eitherend of the fulcrum 20A, 20B and 20C to facilitate retaining a toolwithin the fulcrum 20A, 20B and 20C when levered against it. In theillustrated embodiment, each lip or fulcrum side edge 21 is orientedsubstantially normal to the cutting edge 14 or substantially parallel tothe axis of rotation X of the hole cutter. The illustratedconfiguration, orientation and location of each fulcrum 20A, 20B and 20Cfacilitates engagement of the fulcrum 20A, 20B and 20C by a tool andlevering of the tool against the fulcrum 20A, 20B and 20C to pry orotherwise move a work piece slug out of the interior of the blade body10. Forming at least a portion of the fulcrum surface 20A, 20B and 20Csubstantially parallel to the cutting edge 14, and on the side of theaxially-extending aperture or slot 18 opposite the cutting edge 14,facilitates in levering the tool against the side of the slug oppositethe cutting edge 14 to force the slug out of the interior of the bladebody 10.

As shown in FIG. 1, each slot 18 further defines a side edge 23 that isspaced opposite the fulcrums 20A, 20B and 20C by a minimum width W2 ofthe respective axially-extending slot 18 that is sufficient to allow acommon tool, such as a number 2 screwdriver, to slide axially throughthe axially-extending slot 18 from one fulcrum 20A, 20B or 20C toanother. The minimum width W2 is preferably at least about ¼ inch, ismore preferably within the range of about ¼ inch to about ⅓ inch, and inthe illustrated embodiment, is about 0.27 inch. Also in the illustratedembodiment, the side edge 23 of each axially-extending slot 18 issubstantially smooth and rectilinear to facilitate sliding movement of atool into and through the axially-extending slot 18 (e.g., from onefulcrum 20A, 20B or 20C to another to progressively remove a slug) andto facilitate chip and/or dust egress through the axially-extending slot18. As may be recognized by those of ordinary skill in the pertinent artbased on the teachings herein, the illustrated configuration,orientation, location and dimensions of each fulcrum 20A, 20B and 20Cand axially-elongated aperture or slot 18 are only exemplary, and any ofnumerous other configurations, orientations, locations and/or dimensionsthat are currently known, or that later become known, equally may beemployed.

As shown in FIG. 1, the first fulcrum 20A is axially spaced adjacent tothe cutting edge 14, the second fulcrum 20C is axially spaced furtherfrom the cutting edge 14 as compared to the first fulcrum 20A andadjacent to the rim 16 or non-working end of the hole cutter, and thethird fulcrum 20B is axially spaced between the first and secondfulcrums 20A and 20C. In the illustrated embodiment, the first fulcrum20A is located at approximately one end of the axially-elongatedaperture or slot 18, the second fulcrum 20C is located at approximatelyan opposite end of the aperture or slot 18 relative to the first fulcrum20A, and the third fulcrum 20B is located approximately midway betweenthe first fulcrum 20A and the second fulcrum 20C.

As shown in FIG. 1, the first fulcrum 20A is axially spaced from thecutting edge 14 a first distance D1 within the range of about ½ inch toabout 1 inch, the second fulcrum 20C is angularly spaced relative to thefirst fulcrum 20A and is axially spaced from the cutting edge 14 asecond distance D2 within the range of about 1½ inches to about 2inches, and the third fulcrum 20B is angularly and axially spacedbetween the first and second fulcrums 20A and 20C and is axially spacedfrom the cutting edge 14 a third distance D3 within the range of about 1inch to about 1½ inches. In the illustrated embodiment, the firstdistance D1 of the first fulcrum 20A is configured for levering slugshaving thicknesses of about ½ inch or less, the third distance D3 of thethird fulcrum 20B is configured for levering slugs having thicknesses ofabout 1 inch or less (e.g., a ¾ inch thick plywood slug), and the seconddistance D2 of the second fulcrum 20C is configured for levering slugshaving thicknesses of about 1½ inches or less (e.g., a 2×4 slug). In theillustrated embodiment, the distances D1, D2 and D3 are measured from aplane defined by the cutting edge 14, such as a plane extending betweenthe tips of unset teeth. However, as may be recognized by those ofordinary skill in the pertinent art based on the teachings herein, thedistances between the fulcrums 20A, 20B and 20C and the cutting edge 14,or between other features of the hole cutter and the cutting edge 14,may be measured with respect to any of numerous other reference lines orfeatures that are currently known or used, or that later become known orused, such as from the base of the deepest gullets of the cutting edgeteeth.

In the operation of the hole cutter of FIG. 1, in order to remove, forexample, a relatively thick slug (e.g., a 2×4 slug) or a slug that hastraveled deep into the interior of the bade body 10, a user may insert atool through one of the axially-extending slots 18, place the tip of thetool in contact with the side of the slug facing the cap (not shown) orthe interior of the blade body 10, select the second fulcrum 20C locatedaxially furthest from the cutting edge 14 by placing a distal part ofthe tool into contact with the fulcrum 20C, and apply a force to aproximate portion of the tool to use the tool and the fulcrum 20C tolever the slug towards the cutting edge 14 and out of the interior ofthe blade body 10. If the slug is not removed by levering the toolagainst the second fulcrum 20C, the user can reposition the tool againstthe third or middle fulcrum 20B that is located axially closer to thecutting edge 14 within the same axially-extending slot 18, and use thatfulcrum to lever the slug further towards the cutting edge 14 and/or outof the interior of the hole cutter. Similarly, if the slug is still notremoved from the interior of the blade body 10 by levering the toolagainst the third or middle fulcrum 20B, the user can again repositionthe tool, without having to remove the tool from the respectiveaxially-extending slot 18, against the first fulcrum 20A adjacent to thecutting edge 14, and use the first fulcrum 20A to lever the slug towardsthe cutting edge 14 and out of the interior of the blade body 10. As canbe seen, each axially-extending slot 18 provides multiple fulcrums 20A,20B and 20C that can be used to progressively lever or otherwise work aslug out of the interior of the blade body 10 without having to removethe tool from the respective axially-extending slot 18.

As shown in FIG. 1, the fulcrums 20A, 20B and 20C are both axially andangularly spaced relative to each other such that the fulcrum 20Aadjacent to the cutting edge 14 is located at a first end 22 of theaxially-extending slot 18 closest to the cutting edge 14, the secondfulcrum 20C is located at an opposite or second end 24 of theaxially-extending slot 18, and the third fulcrum 20C is located betweenthe first and second fulcrums 20A, 20C. In the embodiment of FIG. 1, thediameter of the hole cutter is sufficient to include twoaxially-extending slots 18 oriented at acute angles relative to the axisX of the hole cutter. Accordingly, each axially-extending slot 18 ofFIG. 1 is oriented at an acute angle “A” with respect to the axis X ofthe hole cutter. In the currently preferred embodiments, the angle A isat least about 30°, and is preferably within the range of about 35° toabout 60°. In the illustrated embodiment, the acute angle A is about60°. As can be seen, each axially-extending slot 18 slopes away from thecutting edge 14 in a direction opposite the cutting direction of thehole cutter. In the currently preferred embodiments of the hole cutters,the first end 22 of each axially-extending slot 18 is axially spacedfrom the cutting edge 14 a distance D4 within the range of about 15/100inch to about ⅜ inch. One advantage of this configuration is that thefirst or inlet end 22 of each axially-extending slot 18 is spacedclosely adjacent to the cutting edge 14 to receive therefrom the chipsor dust generated at the cutting edge 14 and, in turn, allow such chipsor dust to egress through the axially-extending slot 18 and away fromthe interior of the blade body 10. Yet another advantage of thisconfiguration is that the angular orientation of the axially-extendingslots 18 facilitates in allowing the chips to flow up through theaxially-extending slots 18 and away from the cutting edge 14 andinterior of the blade body 10 as the hole cutter is rotated during acutting operation. A further advantage of the illustrated blade body 10is that the first or inlet end 22 of each axially-extending slot 18 isaxially spaced adjacent to the cutting edge 14 such that a solid orsubstantially solid annular portion 26 of the blade body 10 extendsbetween the first or inlet end 22 of each axially-extending slot 18 andthe cutting edge 14. This annular portion 26 of the blade body 10advantageously provides the blade body 10 with sufficient strength towithstand the heat applied to the blade body 10 during the manufacturingof the hole cutter without distorting the blade body, and providessufficient strength to the hole cutter to withstand the forcesencountered during cutting operations. However, the annular portion 26of the blade body 10 is sufficiently thin (as indicated above, D4 iswithin the range of about 15/100 inch to about ⅜ inch) to allow thechips and dust generated at the cutting edge 14 to flow into theaxially-extending slots 18 and away from the interior of the blade body10.

In FIGS. 2 and 3, another embodiment of a hole cutter of the presentinvention is indicated generally by the reference numeral 100. The holecutter 100 includes a substantially cylindrical blade body 110 that issubstantially the same as the blade body 10 described above inconnection with FIG. 1, and therefore like reference numerals precededby the numeral “1” are used to indicate like elements. The primarydifference between the blade body 110 of FIGS. 2 and 3 and the bladebody 10 describe above is in the shape of the fulcrums 120A, 120B and120C. As can be seen, the fulcrums 120A, 120B and 120C are defined byrecessed curvilinear or radiused edges or surfaces of theaxially-extending slots or apertures 118 that extend angularly in adirection substantially parallel to the cutting edge 114, as opposed torecessed linear edges or surfaces. As shown best in FIG. 3, the radiusedfulcrums 120A, 120B and 120C generally extend angularly in a directionsubstantially perpendicular to the axis of rotation X of the cutter 100,and are curved such that each fulcrum surface 120A, 120B and 120Cinitially extends in a direction away from the cutting edge 114, reachesan apex, and then curves in a direction back towards the cutting edge114. Thus, the radiused fulcrums 120A, 120B and 120C create gullet-likeedges or surfaces wherein the deepest part of each gullet is closest tothe rim 116 or non-working end of the hole cutter 100. In the samemanner as described above in connection with the embodiment of FIG. 1, atool, such as a standard Phillips number 2 screwdriver, can be placedinto contact with the curvilinear fulcrums 120A, 120B and 120C, andpivoted about a respective fulcrum 120A, 120B or 120C to lever a slugout of the interior of the blade body 110. Therefore, the fulcrums 120A,120B and 120C preferably define a radius and/or width W1 sufficient toreceive therein a common tool or implement, such as the elongate shaftof a screw driver. The width W1 is preferably within the range of about¼ inch to about ⅓ inch. The radiused nature of the fulcrums 120A, 120Band 120C is advantageous because the fulcrums 120A, 120B and 120C mimicthe shape of common tools, such as the shaft of a screwdriver. Inaddition, the curvilinear shape of each fulcrum 120A, 120B and 120Claterally supports a tool received within the 120A, 120B or 120C fulcrumto thereby prevent the tool from slipping, sliding or otherwise becomingdisengaged from the fulcrum 120A, 120B or 120C when levering a workpiece slug. As may be recognized by those of ordinary skill in thepertinent art based on the teachings herein, the above-described fulcrumshapes and dimensions are only exemplary, and any of numerous othershapes and/or dimensions that are currently known, or that later becomeknown, equally may be employed.

Another difference between the blade body 110 of FIGS. 2 and 3 and theblade body 10 describe above is the angled orientation of theaxially-extending slots or apertures 118. As shown in FIGS. 2 and 3, theaxially-extending slots or apertures 118 of the blade 110 are set at asmaller acute angle with respect to the axis X of the blade body 110 ascompared to the axially-extending slots or apertures 18 of the blade 10shown in FIG. 1. In the illustrated embodiment shown in FIGS. 2 and 3,the acute angle A is about 47°.

As shown in FIG. 2, the hole cutter 100 includes cap 117 welded to therim 116 of the blade body 110 and forming a part of the non-working endof the hole cutter. The cap 117 includes a central hub 128 defining athreaded aperture for threadedly engaging an arbor, a plurality of drivepin apertures 130 substantially equally spaced relative to each otherabout the central hub 128 for engaging the drive pins of the arbor, anda pair of angularly-extending apertures 132 spaced about 180° apart onopposite sides of the hub 128 relative to each other. Theangularly-extending apertures 132 are dimensioned and positioned toallow insertion therein of a tool, such as a screw driver, to furtherfacilitate in work piece slug removal.

In FIG. 4, another embodiment of a hole cutter of the present inventionis indicated generally by the reference numeral 200. The hole cutter 200includes a substantially cylindrical blade body 210 that issubstantially the same as the blade bodies 10 and 110 described above inconnection with FIGS. 1 through 3, and therefore like reference numeralspreceded by the numeral “2”, or preceded by the numeral “2” instead ofthe numeral “1”, are used to indicate like elements. The primarydifference of the blade body 210 in comparison to the blade bodiesdescribed above is that the axially-extending slots or apertures 218 areoriented substantially parallel to the axis of rotation X of the holecutter 200. The blade body 210 forms a relatively small diameter holecutter 200, and therefore the axially-extending slots 218 cannot defineas large a slot area as the larger diameter hole cutters describedabove, and/or cannot be oriented at acute angles relative to the axis ofrotation X of the hole cutter 200. In the illustrated embodiment, theblade body 210 is used to form hole cutters defining blade bodydiameters within the range of about ⅞ inch to about 1 7/16 inches. Thecurrently preferred embodiments of smaller diameter hole cutters (e.g.,about 13/16 inches diameter or less) define the same slot configurationas illustrated in FIG. 3, but include only one such slot.

Another difference of the blade body 210 is in the shapes of thefulcrums 220A, 220B and 220C. As can be seen, the first fulcrum 220A isdefined by a curvilinear surface extending laterally from theaxially-extending slot 218 substantially parallel to the cutting edge214, but sloping slightly away from the cutting edge 214 in a directionopposite to the cutting direction of the blade 210. The first fulcrum220A includes only one side edge 221 that is oriented substantiallyparallel to the axis of rotation X of the hole cutter. The third ormiddle fulcrum 220B is similarly defined by a curvilinear surfaceextending laterally from the axially-extending slot 218 substantiallyparallel to the cutting edge 214, but sloping slightly away from thecutting edge 214 in a direction opposite to the cutting direction of theblade 210. Like the first fulcrum 220A, the third or middle fulcrum 220Bincludes only one side edge 221 that is oriented substantially parallelto the axis of rotation X of the hole cutter 200, but is curvilinearrather than rectilinear. The second fulcrum 220C is defined by thesecond end 224 of the axially-extending slot 218, and as can be seen, isdefined by a curvilinear surface extending substantially parallel to thecutting direction of the blade 210, and two side surfaces 221 extendingsubstantially parallel to the axis of rotation X of the blade 210 andformed by the respective side edges of the second end 224 of theaxially-extending slot 218. In the illustrated embodiment, the width W2of each of the first fulcrums 220A and the third or middle fulcrums 220Bis preferably within the range of about 2/10 to about ½ inch, and morepreferable within the range of about ¼ to about ⅜ inch. The firstfulcrums 220A and the third or middle fulcrums 220B need not be as wideas the diameter of a number 2 screwdriver, for example, because part ofthe screwdriver shaft can be received in the fulcrum 220A, 220B whileanother portion of the screwdriver shaft can extend into the adjacentportion of the axially-extending slot 218. The width W1 of the thirdfulcrum 220C, on the other hand, is preferably at least about 0.27 inchto allow insertion therein of a number 2 screwdriver.

Another difference of the hole cutter 200 in comparison to the holecutter 100 described above is the configuration of the first or inletend 222 of each axially-extending slot 218. As can be seen, the sideedge 221 of the first fulcrum 220A extends linearly and substantiallyparallel to the axis of rotation X. The first or inlet end 222 of eachaxially-extending slot 218 is defined by two curvilinear regions. Afirst curvilinear region is contiguous to the first fulcrum side edge221 and defined by one or more relatively small radii R1, and a secondcurvilinear region is contiguous to the side edge 223, is defined by oneor more larger radii R2 and is located on an opposite side of theaxially-extending slot 218 relative to the first fulcrum side edge 221.As can be seen, the larger radius R2 imparts a shape to the respectiveedge of the axially-extending slot 218 that slopes away from the cuttingedge 214 in a direction opposite the cutting direction of the blade 210.In addition, the location of the first fulcrum 220A and the orientationof the respective side edge 221 oriented substantially parallel to theaxis of rotation X imparts a relatively wide first end or entranceregion 222 to the axially-extending slot 218 to facilitate the flow ofchips or dust from the cutting edge 214 into the axially-extending slot218. In the illustrated embodiment, the width at the inlet end 222 ofthe axially-extending slot 218 is within the range of about 1¼ to about1½ times the minimum width W1 or width at the outlet end 224 of theaxially-extending slot 218, and preferably is at least about 1⅓ timesthe width W1.

In FIG. 5, another embodiment of a hole cutter of the present inventionis indicated generally by the reference numeral 300. The hole cutter 300includes a substantially cylindrical blade body 310 that issubstantially the same as the blade body 210 described above inconnection with FIG. 4, and therefore like reference numerals precededby the numeral “3” instead of the numeral “2”, are used to indicate likeelements. The primary difference of the blade body 310 in comparison tothe blade bodies described in connection with FIG. 4 is that theaxially-extending slots or apertures 318 define two fulcrums 320A, 320Cinstead of three fulcrums. In the illustrated embodiment, the blade body310 is used to form hole cutters defining blade body diameters withinthe range of about ⅞ inch to about 1 7/16 inches. The currentlypreferred embodiments of smaller diameter hole cutters (e.g., about13/16 inches diameter or less) define the same slot configuration asillustrated in FIG. 5, but include only one such slot. The secondfulcrum 320C is axially spaced from the cutting edge 314 a distance D2within the range of about 1½ inches to about 2 inches. As noted above,the second fulcrum 320C being located in this range is advantageouslyconfigured for levering slugs from 2-by wood (e.g., 2×4, 2×6, 2×8,etc.), such as slugs of about 1⅝ inches or less.

The hole cutters of the present invention may include one or morefeatures of the hole cutters disclosed and/or claimed in any of thefollowing co-pending patent applications that are assigned to theassignee of the present invention and are hereby expressly incorporatedby reference in their entireties as part of the present disclosure: theU.S. patent Application filed on even date herewith, Attorney Docket No.97309.00203, and entitled “Coated Hole Cutter”; the U.S. patentApplication filed on even date herewith, Attorney Docket No.97309.00205, and entitled “Hole Cutter With Minimum Tooth Pitch to BladeBody Thickness Ratio”; the U.S. patent Application filed on even dateherewith, Attorney Docket No. 97309.00196, and entitled “Hole CutterWith Extruded Cap”; the U.S. patent application filed on even dateherewith, Attorney Docket No. 97309.00206, and entitled “Hole CutterWith Chip Egress Aperture”; the U.S. Design patent application filed oneven date herewith, Attorney Docket No. 97309.00209, and entitled “HoleSaw”; and the U.S. Design patent application filed on even dateherewith, Attorney Docket No. 97309.00212, and entitled “Hole Saw”.

It may be readily understood by those having skill in the pertinent artfrom the present disclosure that any of numerous changes andmodifications may be made to the above-described and other embodimentsof the present invention without departing from the scope of theinvention as defined in the appended claims. For example, the holecutters may be made from any of numerous different materials, in any ofnumerous shapes, taking any of numerous different dimensions. Forexample the cutting edge may be made from any of numerous differentmaterials or combinations of materials that are currently known or thatlater become known. As an example, the cutting edge may take any form,pattern, arrangement or configuration that is currently known or thatlater becomes known, including without limitation, tooth patterns thattend to function well in specific applications, hybrid applications orgeneral applications. For example, the cutting teeth may define any ofnumerous different tooth forms, pitch patterns and/or set patterns. Asanother example, a single aperture may be provided in the body of thecutter, two or more apertures may be angularly and/or axially alignedwith one another, or two or more apertures may be variably angularlyand/or axially spaced relative to one another. Also, the hole cuttersmay be used in any of numerous different cutting applications, on any ofnumerous different work piece materials, such as woods, metals,plastics, composites, resins, stones, fabrics, foams, etc. Further, oneor more apertures may extend to the cutting edge, to the rim of the sidewall or cap, or even extend to both the cutting edge and to the rim ofthe side wall or cap. As another example, the length or width of eachfulcrum may not be the same from fulcrum to fulcrum or aperture toaperture. As yet another example, the fulcrum surfaces may not extendlinearly in a direction perpendicular to the axis of rotation of thecutter about the circumference of the cutter. Instead, the fulcrumsurfaces may define curved, curvilinear, rectilinear, angled surfacesand/or combinations of the foregoing. Still further, the aperture sideedges may not extend linearly and axially to define the angular width ofthe angled slots or apertures and connect the outer-lying fulcrums tothe bottom edge surface of the apertures by radiused corners. Instead,for example, the aperture side edges may be curved, curvilinear,rectilinear, angled and/or any combination of the foregoing, and theintersections of the aperture side edges and the end surfaces of theapertures and the outer-lying fulcrums may be right, obtuse and/or acuteintersections, or may define rectilinear and/or curvilinear corners.Similarly, the surfaces that extend between the fulcrums may not belinear and the transitions between the surfaces may not be defined byradiuses. As an alternative, for example, these surfaces may be curved,curvilinear, rectilinear and/or alternatively angled, and thetransitions between these surfaces may be right, obtuse and/or acuteintersections or may define curvilinear and/or rectilinear corners. Asanother example, additional surfaces may be included, or surfaces may beremoved, from the apertures, such as surfaces located adjacent to, orbetween, the fulcrums. In addition, the axially-elongated apertures orslots may define a different number of fulcrums or like surfaces thanillustrated herein, or some axially-elongated apertures or slots maydefine a different number of type of fulcrums than other apertures orslots of the same hole cutter. Accordingly, this detailed description ofthe currently preferred embodiments of the present invention is to betaken in an illustrative, as opposed to a limiting sense.

What is claimed is:
 1. A hole cutter comprising: a substantiallycylindrical blade body defining a cutting edge; and at least oneaxially-elongated aperture formed through the blade body and spaced fromthe cutting edge such that a portion of the blade body extends betweenthe cutting edge and the axially-elongated aperture, wherein theaxially-elongated aperture is configured to receive therethrough a leverfor removing a work piece slug from an interior of the blade body, andthe blade body defines within the axially-elongated aperture a pluralityof fulcrums configured for engaging the lever and for levering slugs outof the interior of the blade body by applying a sufficient leveringforce against the fulcrums to lever a slug towards the cutting edge, theplurality of fulcrums including a first fulcrum axially spaced adjacentto the cutting edge, a second fulcrum axially spaced further away fromthe cutting edge than the first fulcrum, and further comprising a thirdfulcrum.
 2. A hole cutter as defined in claim 1, wherein the thirdfulcrum is spaced a different distance from the cutting edge than thefirst and second fulcrums.
 3. A hole cutter as defined in claim 1,wherein the third fulcrum is angularly spaced around the circumferenceof the blade body relative to the first and second fulcrums.
 4. A holecutter as defined in claim 1, wherein the third fulcrum isaxially-aligned with the first fulcrum.
 5. A hole cutter as defined inclaim 1, wherein the hole cutter defines a direction of rotation that isa cutting direction of the cutting edge, and the first, second and thirdfulcrums are spaced a different distance from the cutting edge from eachother and angularly spaced around the circumference of the blade bodyfrom each other in the direction of rotation in order of decreasingdistance from the cutting edge of said fulcrums.
 6. A hole cutter asdefined in claim 1, wherein the third fulcrum defines a radius orradiused surfaces.
 7. A hole cutter as defined in claim 1, wherein thethird fulcrum defines a surface oriented substantially normal to thecutting edge or substantially parallel to an axis of rotation of thehole cutter.
 8. A hole cutter as defined in claim 1, wherein the thirdfulcrum defines a surface oriented substantially parallel to the cuttingedge.
 9. A hole cutter as defined in claim 1, wherein the third fulcrumdefines a fulcrum surface that is curved, curvilinear, rectilinear, or acombination thereof.
 10. A hole cutter as defined in claim 1, whereinthe third fulcrum defines a plurality of fulcrum surfaces, including afirst fulcrum surface oriented substantially parallel to the cuttingedge, and at least one second fulcrum surface oriented substantiallynormal to the first fulcrum surface.
 11. A hole cutter comprising: asubstantially cylindrical blade body defining a cutting edge; at leastone axially-elongated aperture formed through the blade body and spacedfrom the cutting edge such that a portion of the blade body extendsbetween the cutting edge and the axially-elongated aperture, wherein theaxially-elongated aperture is configured to receive therethrough a leverfor removing a work piece slug from an interior of the blade body, andthe blade body defines within the axially-elongated aperture a pluralityof fulcrums configured for engaging the lever and for levering slugs outof the interior of the blade body by applying a sufficient leveringforce against the fulcrums to lever a slug towards the cutting edge, theplurality of fulcrums including a first fulcrum axially spaced adjacentto the cutting edge, a second fulcrum axially spaced further away fromthe cutting edge than the first fulcrum, and a second aperture formedthrough the blade body and spaced from the cutting edge such that aportion of the blade body extends between the cutting edge and thesecond aperture, wherein the second aperture is angularly spaced aroundthe circumference of the blade body relative to the first and secondfulcrums and defines a fulcrum.
 12. A hole cutter as defined in claim11, wherein the second aperture defines a first end axially spacedadjacent to the cutting edge within a range of about 15/100 inch toabout ⅜ inch.
 13. A hole cutter as defined in claim 12, wherein thesecond aperture defines a second end that is axially spaced further awayfrom the cutting edge than the first end.
 14. A hole cutter as definedin claim 11, wherein the second aperture defines a minimum width ofabout 0.27 inch to allowance insertion of a number 2 screwdrivertherethrough.
 15. A hole cutter as defined in claim 11, wherein saidfulcrum defined by the second aperture is spaced a different distancefrom the cutting edge than the first and second fulcrums.
 16. A holecutter as defined in claim 11, wherein said fulcrum defined by thesecond aperture is angularly spaced around the circumference of theblade body relative to the first and second fulcrums.
 17. A hole cutteras defined in claim 11, wherein said fulcrum defined by the secondaperture defines a radius or radiused surfaces.
 18. A hole cutter asdefined in claim 11, wherein said fulcrum defined by the second apertureis defines a surface oriented substantially normal to the cutting edgeor substantially parallel to an axis of rotation of the hole cutter. 19.A hole cutter as defined in claim 11, wherein said fulcrum defined bythe second aperture defines a surface oriented substantially parallel tothe cutting edge.
 20. A hole cutter as defined in claim 11, wherein saidfulcrum defined by the second aperture defines a fulcrum surface that iscurved, curvilinear, rectilinear, or a combination thereof.
 21. A holecutter as defined in claim 11, wherein said fulcrum defined by thesecond aperture defines a plurality of fulcrum surfaces, including afirst fulcrum surface oriented substantially parallel to the cuttingedge, and at least one second fulcrum surface oriented substantiallynormal to the first fulcrum surface.